Exercise induced coronary inflammation in masters athletes

Background

Chronic endurance exercise has been linked to increased prevalence of coronary artery disease (CAD) in male master athletes. Data are limited regarding the presence of exercise-induced coronary inflammation and its association with atherosclerosis in master endurance athletes. Human coronary inflammation can be detected non-invasively by imaging pericoronary adipose tissue (PCAT). We tested the hypothesis that chronic endurance exercise leads to increased prevalence of atherosclerosis via coronary inflammation.

Methods

Computed tomography coronary angiogram CTCA scans from 2 cohorts of master athletes and age-matched controls, without known risk factors for CAD, were analysed post-hoc and the PCAT attenuation index was calculated around the proximal right coronary artery (FAIRCA). The athletes and the healthy controls also underwent an electrocardiogram, an echocardiogram, a cardiopulmonary exercise test (CPET), a 24-hour Holter tape and a Cardiac Magnetic Resonance (CMR) scan.

Results

Scans from 243 masters endurance athletes (62% females) and 58 age and Framingham CAD risk score matched healthy controls were analysed. FAIRCA was significantly higher (less negative) in male masters athletes vs female masters athletes [−61.3 Hounsfield Units (HU) vs −62.8 HU, p=0.01], in male athletes vs male controls (−61.3 HU vs −68.6 HU, p<0.001) and in female athletes vs female controls (−62,8 HU vs −67.5 HU, p=0.005). In female masters athletes, peak oxygen consumption during CPET (peak VO2) statistically significantly predicted the FAIRCA, F(1,146) = 22.62, p<0.0001. There was no correlation between the FAIRCA and presence of atherosclerosis in male masters athletes.

Conclusions

Masters athletes show increased markers of coronary inflammation. This effect appears to be greater in male masters athletes and is associated with a higher peak VO2 in female masters athletes. However, we did not identify a link between coronary inflammation and coronary atherosclerosis in this cohort.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Cardiac Risk in the Young, UK

Advanced microstructural substrate detection in pre-hypertrophic HCM and its relationship to arrhythmogenesis; a hybrid CMR-ECG-Imaging study

Background

Hypertrophic cardiomyopathy is defined in three domains; clinically by unexplained hypertrophy, genetically by sarcomeric gene mutations and histologically by disarray, small vessel disease and fibrosis. Both ischaemia and myocyte disarray have been implicated in arrhythmogenesis and sudden cardiac death but whether disarray occurs before hypertrophy and its relationship to ischaemia is unknown.

Diffusion-tensor CMR, perfusion mapping & ECG Imaging (ECGI) can measure disarray, ischaemia and electrical aberrance respectively in vivo. We aimed to investigate these in genotype positive (G+) subjects without hypertrophy (LVH−) to identify further subclinical manifestations of gene expression and whether these relate to ventricular arrhythmia formation.

Methods

Diffusion-tensor CMR (3-Tesla) using a motion-compensated spin-echo sequence was acquired in 3 short-axis slices. Quantitative adenosine stress perfusion mapping was performed using standard clinical protocols. A novel ECGI vest, containing 256 unipolar electrodes acquired a 5-minute recording of body-surface potentials to quantify conduction and repolarisation dynamics intervals.

Results

ECGI/CMR was performed on 68 mutation carriers from 64 families and 24 age sex and ethnicity matched healthy controls. Of the mutation carriers, median age was 33 (24–41 years), 57% (39) were female, and 79% (54) were white. Mutations were 39 (57%) MYBPC3, 19 (28%) MYH7, 1 (1%) MYL2 and 9 (12%) were thin filament/non-sarcomeric mutations. There was no significant difference in ejection fraction or LV mass, however G+LVH− had a higher maximum wall thickness (9 (9–10) vs 8 (7–9) mm p=0.003).

Compared to healthy volunteers, G+LVH− individuals had more perfusion defects (18/64 (30%) vs 0, p=0.004), lower Fractional Anisotropy (FA) (suggestive of more disarray) (0.32±0.02 vs 0.34±0.02, p<0.0001) and more prolonged Activation–Recovery Intervals (ARI, a surrogate for action potential duration (259±40 vs 240±31 ms, p=0.03).

In G+LVH−, patients with perfusion defects had more prolonged ARI (263 (248 vs 292) vs 246 (225–283) ms, p=0.03) and lower FA suggestive of more disarray (0.32±0.2 vs 0.31±0.1, p=0.04).

Conclusion

Ischaemia, myocyte disarray and electrical abnormalities occur even in the absence of hypertrophy in HCM. These abnormalities associate to form a complex a clinical phenotype.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): British Heart FoundationBarts Charity

Quantitative myocardial blood flow as a prognostic marker for cardiovascular outcomes in patients with Type 2 Diabetes Mellitus: a multicentre study

 

Introduction: Patients with Type 2 Diabetes Mellitus (T2DM) are at increased risk of cardiovascular disease, including epicardial coronary heart disease, silent myocardial infarction (MI), and coronary microvascular dysfunction (CMD) [1]. All of these can be assessed and quantified using cardiac magnetic resonance (CMR), including most recently quantitative myocardial blood flow (MBF). We aimed to determine the prognostic relevance of MBF in patients with T2DM and test the hypothesis that impaired stress MBF and myocardial perfusion reserve (MPR) have independent prognostic value over standard clinical and imaging parameters.

Methods

A 4-centre study of patients with T2DM who underwent quantitative perfusion assessment using CMR. Diagnosis of T2DM was based on Hba1c >48mmol/l or a known diagnosis of T2DM. Image analysis was performed automatically using an artificial intelligence approach deriving global MBF and MPR [2]. Cox proportional hazard models adjusting for comorbidities and CMR parameters sought associations between stress MBF and MPR with death and major adverse cardiovascular events (MACE), including MI, non-fatal stroke, heart failure hospitalisation and death.

Results

A total of 630 patients with T2DM were included with a median follow-up of 722 days (interquartile range 493) days. There were 27 (4.3%) deaths and 76 MACE events in 62 (12.1%) patients. Patient data was represented into groups depending on threshold stress MBF values of 1.94ml/g/min and MPR thresholds of 1.96 using validated data from invasive coronary physiology [3]. Patient demographics and CMR data are seen in table 1. Kaplan-Meier curves are seen in figure 1. Stress MBF was associated with mortality and MACE after adjusting for age, LV ejection fraction and HbA1c. The stress MBF adjusted hazard ratios for all cause death and death and MACE were 0.35 (95% CI, 0.13–0.95, P=0.04) and 0.54 (95% CI, 0.30–0.96, P=0.04), respectively. MPR was not significantly associated with death and MACE after adjusting for age, LV ejection fraction and HbA1c; hazard ratio for all cause death and death and MACE was 0.83 (95% CI, 0.41–1.69, P=0.60) and 0.81 (95% CI, 0.53–1.23, p=0.32) respectively.

Conclusion

In patients with T2DM, reduced stress MBF measured automatically inline using artificial intelligence quantification of cardiovascular magnetic resonance perfusion mapping provides a strong, independent predictor of adverse cardiovascular outcome.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): 1. REC ID 14/EE/0007 (Barts Heart Centre funding). 2. For PREDICT (Leicester data) ethical approval was provided by the UK Health Research Authority Research Ethics Committee (reference 17/WM/0192). 3. MATCH Study, Leeds - British Heart Foundation - 17/YH/0300. 4. LEAN-DM, Leeds - British Heart Foundation - 18/YH/01685. CEED, Leeds: British Heart Foundation - REC reference - 18/YH/0190

Heterozygous APOE ε4 carriage associates with improved myocardial efficiency in older age

Background

Carriage of the ancestral APOE ε4 allele confers a risk of developing Alzheimer's and coronary artery disease, but its persistence in human populations also suggests some potential survival advantages. To date it remains unclear whether APOE ε4 carriage independently associates with a better or worse long-term cardiac phenotype.

Purpose

Using data from the 1946 National Survey of Health and Development (NSHD) birth cohort, we investigated whether APOE ε4 carriage associates with adverse or beneficial left ventricular (LV) size and function parameters by echocardiography in older age.

Methods

Based on the presence or absence of APOE ε4, genotypes were divided into: non-APOE ε4 (ε2ε2, ε2ε3, ε3ε3), heterozygous-APOE ε4 (ε2ε4 and ε3ε4) and homozygous-APOE ε4 (ε4ε4). Echocardiographic data at 60–64 years included: left ventricular ejection fraction (LV EF), E/e', systolic and diastolic LV posterior wall and interventricular septal thickness (LVPWTs/d, IVSs/d), and body-surface area indexed LV mass (LVmassi) and myocardial contraction fraction (MCFi). Generalized linear models explored associations between APOE ε4 genotypes as exposures and echocardiographic biomarkers as outcomes. As a combination of gene variants, APOE ε genotype is expected to be an instrumental variable and therefore unconfounded. Thus, Model 1 was unadjusted. To obtain more precise regression estimates, Model 2 was adjusted for factors associated with the outcome, namely sex and socio-economic position (SEP). To explore the mechanistic pathway downstream of APOE ε genotype but upstream of the echocardiographic outcomes, subsequent models were adjusted for mediators as follows: Model 3 for body mass index, Model 4 for the presence of cardiovascular disease (CVD), Model 5 for diabetes, Model 6 for high cholesterol and Model 7 for hypertension.

Results

1464 participants were included. Compared to non-APOE ε4 and homozygous groups, heterozygous-APOE ε4 individuals had similar cardiac phenotypes in terms of EF, E/e', LVPWTs/d, IVSs/d and LVmassi but had a 7% higher MCFi 95% confidence interval [CI]: 1%-13%, p=0.017) which persisted even after adjustment for sex and SEP (95% CI 1%-12%, p=0.026) that was attenuated to 6% after adjustment for CVD (95% CI 0–13% p=0.050) and hypertension (95% CI 1–13% p=0.022).

Conclusion

The heterozygous-APOE ε4 state associates with improved myocardial shortening in older age resulting in greater LV stroke volume generation per 1 mL of myocardium. As we found no association between APOE ε4 carriage and LVPWTs/d, IVSs/d or LVmassi, MCFi enhancement may be mediated by improved myocardial energetics and contractility, with calcium and androgens potentially implicated, rather than through pathological ventricular thickening. Although a dose relationship is normally expected with ε4 carriage, any benefit from increased energetics and contractility is likely to be counterbalances by the higher risk of CVD and cardiovascular risk factors.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK Medical Research Council British Heart Foundation

Convolutional neural network transformer (CNNT) for free-breathing real-time cine imaging

Funding Acknowledgements

Type of funding sources: None.

Background

Real-time cine imaging does not require breath-holding and is a robust cine imaging technique in the presence of irregular heartbeats. It is a good alternative to the conventional breath-hold retro-gated cine for simplified acquisition and improved patient comfort. Real-time acquisition is achieved with the single-shot BSSFP readout without retro-gating. To maintain good temporal and spatial resolution, higher acceleration (e.g. >4x parallel imaging) is required. As a result, the real-time cine images experience reduced signal-to-noise ratio (SNR), which limits its clinical acceptance.

Purpose

We developed a novel deep learning model architecture, the Convolutional Neural Network Transformer (CNNT), to improve the quality of real-time cine, under 4x, 5x and 6x acceleration.

Method

Convolutional Neural Networks (CNN) are widely used in CMR research to process cardiac images. Cardiac images are often acquired as a time series with strong inter-phase correlation. We combined the CNN with the more recent transformer model to develop a novel CNNT architecture. It takes in the entire 2D+T time series as input and has advantages of CNN for efficient computation and spatial invariance. It further inherits the advantages of attention layer in the transformer and is able to efficiently utilize the temporal correlation within a time series.

A CNNT model is developed to improve the SNR of real-time cine imaging. N=10 patients were scanned at a heart center, with 4x, 5x and 6x acceleration. Typical imaging parameters are: FOV 360×270mm2, flip angle 50°, acquired matrix size 160×90 for R=4 acceleration, 192×108 for R=5 and 6, temporal resolution 40ms for R=4, 42ms for R=5 and 35ms for R=6. The real-time images went through a TGRAPPA reconstruction [1] and the CNNT model. The SNR of TGRAPPA was measured with SNR units [2]. The Monte-Carlo pseudo-replica test was used to measure SNR for the CNNT model. For every cine series, two phases were picked for the end-systole and end-diastole. For every image picked, two region-of-interests were drawn in the myocardium and in the LV blood pool. The CNNT model was deployed inline on the MR scanner using the Gadgetron InlineAI [3].

Results

Figure 1 gives real-time cine images for three accelerations, reconstructed with TGRAPPA and CNNT. The parallel imaging TGRAPPA reconstruction suffers significant SNR loss from elevated g-factor and less acquired data. The deep learning CNNT model recovered SNR even at the very high 6x acceleration, without observed loss of boundary sharpness.

Table 1 lists the SNR measurement results. The TGRAPPA SNR decreased ∼4x from R=4 to R=6 for both the blood and myocardium. For the blood, the CNNT increased the SNR by 170%, 335%, 371% at R=4, 5 and 6. For the myocardium, the SNR increases were 335%, 634% and 828%.

Conclusion

We developed a convolutional neural network transformer model to recover the SNR for real-time cine imaging at higher acceleration.

Asymmetric septal thickening is observed in hypertrophic cardiomyopathy mutation carriers without left ventricular hypertrophy: insights from AI analysis

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Hughes is supported by the British Heart Foundation (grant number FS/17/82/33222).

Background

Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac disease characterised by left ventricular hypertrophy (LVH), often, with asymmetric septal thickening. Despite the prevalence of inherited mutations present in >50% of cases, there is variable phenotypic expression in those with abnormal sarcomere protein genes. In individuals with abnormal genes but without LVH, we hypothesised that there is subtle asymmetric septal hypertrophy, detectable by the increased precision offered by an artificial intelligence (AI) tool for measuring wall thickness.

Purpose

We explored the septal-lateral ratio measured by AI in individuals with an identified genotype but no left ventricular hypertrophy as a component of sub-clinical HCM.

Methods

43 individuals with identified genotype, but no left ventricular hypertrophy (G+LVH-) and 97 age-, sex- and disease-matched controls underwent CMR. Patients were excluded if they had a maximum wall thickness (MWT) of ≥13mm. A clinically validated AI tool was used to measure the MWT, for each segment in the 16-segment AHA model. The septal-lateral ratio was calculated using the septal segment with the largest MWT and the lateral segment with the largest MWT.

Results

The mean septal-lateral ratio of the G+LVH- patients was 1.22 (SD 0.22) and the mean septal-lateral ratio of the matched controls was 1.14 (SD 0.15) with a statistically significant mean difference of 0.08 (p=0.01). There was no significant difference between the MWT of the G+LVH- patients at 10.3mm (SD 2.2) and healthy volunteers at 10.1mm (SD 1.8) (p = 0.61).

Conclusion

G+LVH- patients have a 7% increase in their septal-lateral ratio compared with age-matched controls despite the lack of difference in the MWT. Using increased precision offered by AI, early features of HCM can be observed in patients without overt LVH.

CNNT DB-LGE: free-breathing dark blood late enhancement imaging using the convolutional neural network transformer speeds acquisition by 50%

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported in part by the Division of Intramural Research of the National Heart, Lung, and Blood Institute, National Institutes of Health (grants Z1A-HL006214-05 and Z1A-HL006242-02).

Background

Dark blood late gadolinium enhancement (DB-LGE) imaging shows superior delineation of myocardial infarction (MI), especially at the sub-endocardial boundary. Our previous study [1] developed a free-breathing DB-LGE with the single shot SSFP readout, phase sensitive inversion recovery (PSIR) reconstruction, and respiratory motion corrected averaging. To compensate the potential signal-to-noise ratio loss, our previous DB-LGE doubled the measurements, thereby increasing the acquisition time.

Purpose

In this study, we developed a deep learning image enhancement model using a novel neural network architecture called the convolutional neural network transformer (CNNT) to improve the image quality of DB-LGE and to reduce the acquisition time by decreasing the number of measurements.

Methods

A novel image enhancement model was developed using a novel network architecture called the Convolutional Neural Network Transformer (CNNT) proposed by us. This architecture is suitable for the 2D+Time CMR acquisition, by exploiting the temporal correlation between images over multiple averages.

The evaluation was first retrospectively conducted on a cohort of 12 patients acquired with the original protocol [1] using the full 16 measurements. For every subject, a complete short-axis stack (typically 12 slices) was acquired to cover the entire left ventricular. The imaging data was reconstructed in three ways. Original: using all acquired 16 measurements. This is our base-line protocol. Original 50%: using only the first 8 measurements. CNNT 50%: using only the first 8 averages, but performing the CNNT deep learning image enhancement before MOCO PSIR reconstruction. Two experienced imaging researchers (PK and MF, >10 years of experience for both) scored all DB-LGE images for the overall quality, diagnostic confidence and delineation of MI/boundaries (5 = excellent, 4 = good, 3 = fair, 2 = poor, and 1 = non-diagnostic). The CNNT DB-LGE was deployed to the MR scanner using the Gadgetron InlineAI [2].

Results

Figure 1 gives examples of DB-LGE with three reconstruction methods. The CNNT image has higher SNR and well delineated MI. The Original images with the longest acquisition have good quality and the Original-50% acquired with 8 measurements are good quality but have reduced SNR. The mean scores for overall image quality, diagnostic confidence and MI delineation of two reviewers were 4.88±0.23, 4.88±0.23, 4.83±0.25 for CNNT and 4.96±0.14, 4.96±0.14, 4.67±0.39 for the original approach. No significant differences were found between the original and the CNNT (P>0.15 for all).

Figure 2 shows an acute MI patient prospectively acquired with the 50% scan time reduction, with and without the CNNT enhancement. The resulting PSIR images well delineate the MVO due to the acute MI, with improved SNR.

Conclusion

A novel CNNT model was proposed and evaluated to speed up the free-breathing MOCO DB LGE by 50% without sacrificing image quality.

Improving the diagnostic accuracy of apical hypertrophic cardiomyopathy using machine learning

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Hughes is supported by the British Heart Foundation (grant number FS/17/82/33222).

Introduction

The imaging criteria for diagnosis of apical hypertrophic cardiomyopathy (ApHCM) is a maximum wall thickness (MWT) ≥15mm. CMR enables detection of subtle phenotypic features (e.g. loss of apical tapering, cavity obliteration) and coupled with characteristic electrocardiogram changes, ApHCM can be diagnosed without overt hypertrophy. However, these patients are not captured by current diagnostic criteria.

Purpose

We sought to use a machine learning tool to quantify wall thickness and identify patients with ‘relative’ ApHCM that do not reach current diagnostic thresholds.

Methods

CMR images from 4118 healthy participants from the UK Biobank were segmented automatically with a clinically validated machine learning algorithm and wall thickness measured at all point in the myocardium by solving a solution to Laplace’s equation. MWT were pooled into 16 AHA segments and indexed to body surface area (BSA). The non-indexed and indexed segmental upper limit of normal was calculated as the mean + 3 standard deviations (the equivalent of 95% confidence interval after correcting for multiple [16] comparisons using the Bonferroni method).

Results

73 overt ApHCM subjects (MWT>15mm) and 31 relative ApHCM subjects underwent CMR scanning. In healthy controls, the non-indexed (and indexed) upper limits were calculated for the apical-anterior 10.2mm (5.2 mm/m2), apical-septal 11.1mm (5.6 mm/m2), apical-inferior 10.5mm (5.3 mm/m2) and apical-lateral 10.1mm (5.2 mm/m2) segments. With a non-indexed cut-off, all (73 of 73) overt ApHCM and 84% (26 of 31) relative ApHCM were classified as having an abnormally thick apex. 3% (127 of 4118) of the healthy UK Biobank cohort were classified as abnormal, as expected. Using an indexed cut-off, all overt ApHCM and 87% (27/31) relative ApHCM were classified as abnormal, and 3% (123 of 4118) of the healthy UK Biobank cohort were misclassified.

Conclusion

We can successfully classify 87% of relative ApHCM patients from a normative reference range derived from a large cohort of healthy patients – a significant improvement on existing methods. We show that the specificity and sensitivity is increased when MWT is indexed to BSA. For practical clinical application, we recommend a cut-off of 10mm or an indexed cut-off of 5mm/m2 in any apical segment to diagnose apical LVH. Overt and relative apical HCM examplesHealthy controls AHA maps (non-indexed)

Speeding up cardiac MR segmentation with semi-supervision: applications in cine imaging

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): This material is based upon work supported by the Google Cloud Research Credits program with the award GCP19980904.

Background

Segmentation is an important postprocessing step in cardiac magnetic resonance (CMR) imaging that enables quantitative assessment of functional parameters. Deep learning can automate the segmentation process, producing accurate contours of cardiac structures while reducing the time required to analyze images and the interobserver variation compared to manual analysis. However, common approaches to training neural networks (NNs) require large amounts of labeled data, which is costly to generate and slows down the development of CMR segmentation NNs for new applications. Semi-supervision is an approach to alleviate this labeling burden by relying on abundant unlabeled data and a smaller amount of labeled data to train NNs.

Purpose

We propose a novel semi-supervised method to train CMR segmentation NNs. We use the proposed method to train NNs to segment the left ventricle in CMR cine images. Ultimately, we aim to show that semi-supervision can drastically reduce the amount of labeled data required to develop machine learning segmentation applications for CMR while maintaining high performance.

Methods

Our dataset consists of 1,208 short-axis cine CMR images and 1,244 long-axis cine CMR images. An expert annotator manually segmented the endocardium on the end-diastolic and end-systolic short-axis and long-axis images and the epicardium on the end-diastolic short-axis images. We split the dataset randomly by patient into 60% training, 20% validation, and 20% testing data. We train semi-supervised segmentation networks using a supervised cross-entropy loss to learn from the labeled training data and a cosine embedding loss in addition to a pseudo-labeling step to learn from the unlabeled training data. To evaluate how performance changes with different amounts of labeled training data, we vary the percent of training data that has labels from <1%-100%. We evaluate the predicted segmentation masks using the Dice coefficient.

Results

Using only 100 labeled image slices, the semi-supervised segmentation NNs achieve a mean Dice coefficient within 1.10% of networks trained with fully labeled training sets, corresponding to >85% reduction in required labeled training data (Table 1). The proposed semi-supervised method improves performance over naïve training by 6.21% for the most limited labeled data setting (i.e., 10 labeled image slices; Figure 1).

Conclusion

We have shown that NNs trained with limited labeled data achieve high performance on left ventricle segmentation in short-axis and long-axis CMR cines. The proposed approach is flexible and broadly applicable to different CMR segmentation tasks, enabling rapid development of segmentation networks for many cardiac structures and applications. Table 1Figure 1

The COVANOS trial - insight into post-COVID olfactory dysfunction and the role of smell training

BACKGROUND

Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted.

METHODOLOGY

We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants.

RESULTS

218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia.

CONCLUSIONS

Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.

Advanced electrocardiography predicts early cardiac involvement and incident arrhythmias in Fabry disease

Funding Acknowledgements

Type of funding sources: None.

Background

Fabry disease is an X-linked disorder, with cardiovascular involvement characterised by progressive myocardial sphingolipid deposition. Cardiac disease is a major contributor to morbidity and mortality. Cardiac magnetic resonance (CMR) with T1 mapping and advanced electrocardiography (A-ECG) offer both diagnostic and prognostic potential.

Purpose

To evaluate the predictive power of A-ECG markers in identifying: 1) early cardiac involvement defined as low myocardial T1 on CMR, and 2) adverse cardiovascular outcomes defined as any arrhythmia requiring therapy, atrial fibrillation, hospitalisation for heart failure or mortality.

Methods

Patients included in this longitudinal, multi-centre study underwent same-day standard resting 12-lead ECG and CMR. CMR included standard cine imaging, T1 mapping with modified Look Locker inversion recovery (MOLLI, 5s(3s)3s), and late gadolinium enhancement (LGE). ECG digital files were analysed using in-house A-ECG software. A-ECG analysis included conventional ECG measures, derived vectorcardiographic measures, and singular value decomposition measures of waveform complexity. Significant A-ECG variables were identified using stepwise forward regression and incorporated in a multivariable logistic regression A-ECG score. A Youden index was applied to identify best threshold score and bootstrapping performed to calculate the area under the receiver operating characteristics curve (AUC), sensitivity, specificity, and 95% confidence intervals (CI).

Results

Among included patients (n=155, 40% male, age 46±14 years, 39% on enzyme replacement therapy), left ventricular mass index was higher in males compared to females (106 vs. 59 g/m2, p<0.001), 80% of patients had myocardial native T1 below the local reference range (933 vs. 968 ms, p=0.06), and 51% (70/136) had focal LGE. Multivariable A-ECG scores for detecting low T1, any arrhythmia, or atrial fibrillation had an AUC [95%CI], sensitivity, and specificity of 0.82 [0.75-0.89], 72 [55-95]%, 85 [66-71]%; 0.89 [0.82-0.95], 82 [68-94]%, 88 [70-96]%; and 0.89 [0.80-0.96], 92 [77-100]%, 83 [76-92]%, respectively, Figure 1. No predictors of heart failure hospitalisation or mortality were found.

Conclusion

A-ECG analysis of the resting 12-lead ECG has good diagnostic performance for predicting early myocardial involvement and the occurrence of arrhythmias in Fabry disease. This supports the use of A-ECG both as a screening tool to diagnose early cardiac disease, and for identifying those at risk of adverse arrhythmic outcomes.

Computed tomography vs cardiovascular magnetic resonance imaging derived extracellular volume fraction in patients with stable new-onset chest pain

Background

Computed tomography (CT) is increasingly recognised as a diagnostic modality across a range of cardiovascular conditions and is now first-line for the investigation of stable new-onset chest pain. Determination of the myocardial extracellular volume fraction (ECV) has been shown to correlate well with the identification and prognostication of disease. Cardiovascular magnetic resonance (CMR) imaging remains the gold standard for the measurement of myocardial ECVCMR using T1-mapping, but there is increasing evidence for the use of ECV by cardiac CT (ECVCT).

Purpose

To assess the performance of ECVCT against the reference standard of ECVCMR.

Methods

Patients with a history of chest pain and no previously documented coronary disease referred for invasive angiography were recruited as part of the EVINCI Heart-QIT study. A cohort of these patients (n=33) underwent CMR at 1.5T (Siemens Aera, Siemens Healthcare, Erlangen/Germany) with T1 mapping of a mid-ventricular short axis slice (by MOdified Look-Locker Inversion recovery [MOLLI]) before and 15 minutes after a bolus of gadolinium contrast (0.1 mmol/kg gadoterate meglumine), followed by whole-heart ECVCT quantification (Somatom Force, Siemens Healthcare, Erlangen/Germany) using a 5-min post-iodine-contrast acquisition protocol. To account for data clustering on a patient level and volumetric discrepancy on a modality level, comparisons were made using mid-ventricular pooled ECVCT and ECVCMR. Bland-Altman analysis was used to determine the limits of agreement and identify systematic differences between both measures.

Results

A total of 33 patients (70% male, mean age 56.8±12.6yr) underwent the combined CMR and CT. ECVCMR and ECVCT were then analysed retrospectively (Figure 1). The average pooled ECV for the 6 mid-ventricular segments for CMR and CT were (27.6±2.4 and 26.8±2.2 respectively). Bland-Altman analysis demonstrated a marginally higher CMR-ECV (0.8±2.1) vs CT-ECV, which is in keeping with the longer delay-time encountered in CMR protocols (Figure 2).

Conclusions

ECVCT obtained from 5-minute post-contrast CT protocols show good agreement with ECVCMR in a stable chest pain patient cohort.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Siemens Helthineers Educational Grant Figure 1. CMR (L) and CT (R) ECV mapsFigure 2. Bland-Altman plot

Childhood bradycardia associates with atrioventricular conduction defects in older age: a longitudinal birth cohort study

Background

A high resting heart rate (RHR) has been associated with cardiovascular morbidity and mortality. However, little is known about the long-term effects of childhood bradycardia.

Purpose

This study aimed to explore the association between childhood bradycardia and later-life cardiac phenotype using longitudinal data from the 1946 Medical Research Council National Survey of Health and Development (NSHD) birth cohort.

Methods

RHR was recorded at ages 6 and 7 to provide the bradycardia exposure defined as a childhood RHR<75. Three outcomes were studied: i) echocardiographic data at 60–64 consisting of ejection fraction (EF), left ventricular mass index (LVmassi), myocardial contraction fraction index (MCFi) and E/e'; ii) electrocardiographic (ECG) evidence of atrio-ventricular (AV) conduction defects (Minnesota categories: 6-1, 6-2-1, 6-2-2, 6-2-3, 6-3, 6-8, 8-5-1, 8-5-2, 8-6-1, 8-6-2, 8-6-3 and 8-6-4) or ventricular conduction defects (any Minnesota group 7) by age 60–64; and iii) all-cause and cardiovascular mortality. Generalized linear models (glm) with gamma distribution were used for echocardiographic analyses, glms with binomial distribution for ECG analyses and Cox proportional hazards models for mortality. Adjustment was made for relevant demographic and health-related covariates, and for multiple testing. In order to account for within-subject correlated repeated measures at 6 and 7 years of age, mixed glms (glmms) were used as a sensitivity analysis. To explore any nonlinear relationships, we modeled each outcome as a sum of best fitting fractional polynomials of RHR at 6 and 7 (as continuous variables) and covariates using a “closed test procedure” with backward elimination.

Results

The number of participants included was: 4381 for mortality, 1631 for ECG and 1617 for echocardiography analyses. Childhood bradycardia was associated with male sex (p<0.0001) and higher BMI (p=0.009). In fully adjusted models, childhood bradycardia was associated with 2.91 higher odds of AV conduction defects (95% confidence interval [CI] 1.59–5.31, p=0.0005), even at a false discovery rate of 0.05. Associations persisted in random coefficients glmm models (odds ratio 2.50, 95% CI 1.01–4.31). The fractional polynomials analyses revealed that the log odds of AV conduction defects at 60–64 years of age were linearly associated with RHR at 7 years. There was no association between bradycardia in childhood and ventricular conduction defects, echocardiographic parameters or mortality outcomes.

Conclusions

Longitudinal data indicate that childhood bradycardia trebles the odds of having AV conduction defects, but does not influence mortality or heart size and function in older age. As one in three older adults with AV conduction defects will have been bradycardic in childhood, future research should concentrate on identifying children at risk, the potential mechanisms involved and whether AV blocking drugs accelerate nodal dysfunction.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): British Heart Foundation (MyoFit46 Special Programme Grant SP/20/2/34841)

MRI provision for patients with cardiac implantable electronic devices: understanding the real-world administrative requirements of service delivery

Introduction

Patients with cardiac implantable electronic devices (CIEDs) should have access to Magnetic Resonance Imaging (MRI) but are less likely to be referred and hospitals lack provision. A major barrier to service delivery is the administrative demand required to obtain accurate CIED details prior to scheduling. We aimed to understand the administrative requirements of a high-volume Cardiac Device-MRI service to inform the design of an electronic referrals platform that can facilitate workflow.

Methods

Single centre retrospective audit of a high-volume Cardiac Device-MRI service in a tertiary unit in the UK. Six months of referrals were reviewed for patient and CIED details and barriers met. Referrals were stratified by source, indication, MR-Conditional labelling and referrer.

Results

Administrative barriers were reviewed for 116 patients with CIEDs referred for MRI (48% cardiac, 52% non-cardiac) between September 2020 and March 2021 (Table 1). Referrers were 47% cardiologists and 53% other specialties. Referral to scan time was 15 days (interquartile range, 8–32). There were no scan-related complications.

34% of referrals contained complete CIED details and 30% stated the MR labelling of the CIED. None incorrectly labelled a CIED as MR-Conditional, but 8% incorrectly labelled as non-MR Conditional. 7 additional days were required to obtain complete CIED details where not provided (involving information requests from two device clinics in 27%), 10% had delays over 2 weeks (maximum 145 days). 35% required 3 or more repeat discussions with referrers after initial referral. Obtaining CIED information for external referrals required 17 days (11–42), compared to 14 (6–35) days for internal referrals (p=0.25).

Patients with non-MR Conditional CIEDs required on average 14 days longer to obtain complete referral details than patients with MR-Conditional CIEDs. Even when referrers were aware of non-MR Conditional labelling and received information on risk, 41% required further discussion between patient and referrer regarding risks and benefits of MRI scanning. For cancer referrals, obtaining correct details took 1 day longer than other referrals (p=0.074) and required 2 extra emails to maintain provision within the national time-to-treatment target of 62 days. Missing data was similarly present in referrals from Cardiologists and non-Cardiologists (59% versus 61% respectively), but non-Cardiologists recorded more incorrect CIED details (8% vs 0%).

Conclusions

Referral for MRI in patients with CIEDs demands significant administrative input to obtain correct device information, leading to delays. These delays are greater for patients with non-MR conditional CIEDs, and data provided is often incorrect or incomplete. This may explain why some patients are not referred for MRI. An online referrals platform has been developed to streamline this process, initially deployed through a network of 60 centres registered in the UK.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This work is supported by British Heart Foundation Innovations funding (HFHF_016).

Myocardial perfusion after COVID-19 infection: No persisting impaired myocardial blood flow in surviving patients

Funding Acknowledgements

Type of funding sources: None.

Background

 Acute myocardial damage is common in hospitalized patients with severe COVID-19, with evidence of myocardial infarction and myocarditis demonstrated on cardiovascular magnetic resonance (CMR). Post-mortem studies have also implicated microvascular thrombosis, which may cause persistent microvascular disease. 

Purpose

 To determine the long-term coronary sequelae in recovered COVID-19 using multiparametric CMR including state-of-the-art inline quantitative stress myocardial blood flow (sMBF) mapping to assess global and regional sMBF.

Methods

 Prospective, multicentre observational study of recovered COVID-19 patients scanned at three London CMR units. Results were compared to a propensity-matched, pre-COVID chest pain cohort (104 patients referred for perfusion CMR, with subsequently demonstrated unobstructed coronary arteries) and 27 healthy volunteers (HV). Perfusion image analysis was performed using a novel artificial intelligence approach deriving global and regional stress and rest MBF with a cut-off of >2.25mL/g/min signifying normal sMBF and <1.82mL/g/min abnormal sMBF (Kotecha JCVI 2019). 

Results

 104 recovered, post-COVID patients (median age 62 years, 76% male; 89[87%] hospitalised, 41/89[46%] requiring ICU) underwent adenosine-stress perfusion CMR at a median 131(IQR 43-179) days from COVID-19 diagnosis. Median LVEF was 67% (IQR 60-71%; 12 (11.5%) with impaired LVEF), 51 patients (49%) had late gadolinium enhancement (LGE); 18% infarct-pattern and 33% non-ischaemic LGE.  Global stress MBF in post-COVID patients was no different to age-, sex- and co-morbidities-matched controls (2.57 ± 0.77 vs. 2.40 ± 0.75 ml/g/min, p = 0.11, Figure 1), though lower than HV (3.00 ± 0.76 ml/g/min, p = 0.001). Post-COVID, multivariate predictors of low sMBF were male sex (OR 0.57, 95%CI 0.41-0.80, p = 0.001) and hypertension (OR 0.67, 95%CI 0.51-0.88, p = 0.004), but not COVID-19 disease severity (ICU admission) or presence of scar (ischemic/non-ischemic).  21/42 with reduced sMBF (<2.25mL/g/min) had regional perfusion defects consistent with epicardial coronary disease.

Conclusions

  COVID-19 survivors do not demonstrate evidence of reduced global MBF by CMR compared to risk factor matched controls. Stress perfusion CMR identifies etiology of acute myocardial damage (infarction/myocarditis) and presence of occult coronary ischemia.

Prospective case-control study of cardiovascular abnormalities six months following mild COVID-19 in healthcare workers

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Barts Charity UCLH Charity

OnBehalf

COVIDsortium

Background

Recent CMR studies have reported cardiac abnormalities after COVID-19 are common, even after mild, non-hospitalised illness with evidence of ongoing myocardial inflammation.  Such a prevalence of chronic myocarditis after mild disease has prompted societal concerns in diverse domains, and suggests that screening should be considered post COVID-19, even in asymptomatic individuals.  Cardiovascular magnetic resonance (CMR) has proven utility for diagnosis in patients with COVID-19 infection and elevated troponin from unclear causes by measuring cardiac structure, function, myocardial scar (late gadolinium enhancement) and oedema (T1 and T2 mapping).

Objectives

We aimed to determine the prevalence and extent of late cardiac and cardiovascular sequelae after mild non-hospitalised SARS-CoV-2 infection.

Methods

Participants were recruited from COVIDsortium, a three-hospital prospective study of 731 healthcare workers who underwent first wave weekly symptom, PCR and serology assessment over 4 months, with seroconversion in 21.5% (n = 157). At 6 months post infection, 74 seropositive and 75 age-, sex-, ethnicity-matched seronegative controls were recruited for cardiovascular phenotyping (comprehensive phantom-calibrated Cardiovascular Magnetic Resonance and blood biomarkers). Analysis was blinded, using objective AI analytics where available.

Results

149 subjects (mean age 37 years, range 18-63, 58% female) were recruited. Seropositive infections had been mild with case definition/non-case definition/asymptomatic disease in 45(61%), 18(24%) and 11(15%) with one person hospitalised (for 2 days). Between seropositive and seronegative groups, there were no differences in cardiac structure (left ventricular volumes, mass; atrial area), function (ejection fraction, global longitudinal shortening, aortic distensibility), tissue characterisation (T1, T2, ECV mapping, late gadolinium enhancement) or biomarkers (troponin, NT-proBNP).  With abnormal defined by the 75 seronegatives (2 standard deviations from mean, e.g. EF &lt; 54%, septal T1 &gt; 1072ms, septal T2 &gt; 52.4ms), individuals had abnormalities including reduced EF (n = 2, minimum 50%), T1 elevation (n = 6), T2 elevation (n = 9), LGE (n = 13, median 1%, max 5% of myocardium), biomarker elevation (borderline troponin elevation in 4; all NT-proBNP normal). These were distributed equally between seropositive and seronegative individuals.

Conclusions

Cardiovascular abnormalities are no more common in seropositive vs seronegative otherwise healthy, workforce representative individuals 6 months post mild SARS-CoV-2 infection.  Our study provides societal reassurance for the cardiovascular health of working-aged individuals with convalescence from mild SARS-CoV-2. Screening asymptomatic individuals following mild diseases is not indicated.

Dark blood ischemic LGE segmentation using a deep learning approach

Funding Acknowledgements

Type of funding sources: None.

Introduction

The extent of ischemic scar detected by Cardiac Magnetic Resonance (CMR) with late gadolinium enhancement (LGE) is linked with long-term prognosis, but scar quantification is time-consuming. Deep Learning (DL) approaches appear promising in CMR segmentation.  Purpose: To train and apply a deep learning approach to dark blood (DB) CMR-LGE for ischemic scar segmentation, comparing results to 4-Standard Deviation (4-SD) semi-automated method. Methods: We trained and validated a dual neural network infrastructure on a dataset of DB-LGE short-axis stacks, acquired at 1.5T from 33 patients with ischemic scar. The DL architectures were an evolution of the U-Net Convolutional Neural Network (CNN), using data augmentation to increase generalization. The CNNs worked together to identify and segment 1) the myocardium and 2) areas of LGE. The first CNN simultaneously cropped the region of interest (RoI) according to the bounding box of the heart and calculated the area of myocardium. The cropped RoI was then processed by the second CNN, which identified the overall LGE area. The extent of scar was calculated as the ratio of the two areas. For comparison, endo- and epi-cardial borders were manually contoured and scars segmented by a 4-SD technique with a validated software. Results: The two U-Net networks were implemented with two free and open-source software library for machine learning. We performed 5-fold cross-validation over a dataset of 108 and 385 labelled CMR images of the myocardium and scar, respectively. We obtained high performance (&gt; ∼0.85) as measured by the Intersection over Union metric (IoU) on the training sets, in the case of scar segmentation. With regards to heart recognition, the performance was lower (&gt; ∼0.7), although improved (∼ 0.75) by detecting the cardiac area instead of heart boundaries. On the validation set, performances oscillated between 0.8 and 0.85 for scar tissue recognition, and dropped to ∼0.7 for myocardium segmentation. We believe that underrepresented samples and noise might be affecting the overall performances, so that additional data might be beneficial. Figure1: examples of heart segmentation (upper left panel: training; upper right panel: validation) and of scar segmentation (lower left panel: training; lower right panel: validation). Conclusion: Our CNNs show promising results in automatically segmenting LV and quantify ischemic scars on DB-LGE-CMR images. The performances of our method can further improve by expanding the data set used for the training. If implemented in a clinical routine, this process can speed up the CMR analysis process and aid in the clinical decision-making. Abstract Figure.

Non-invasive assessment of ventriculo-arterial coupling using aortic wave intensity analysis combining central blood pressure and phase-contrast cardiovascular magnetic resonance

BACKGROUND

Wave intensity analysis (WIA) in the aorta offers important clinical and mechanistic insight into ventriculo-arterial coupling, but is difficult to measure non-invasively. We performed WIA by combining standard cardiovascular magnetic resonance (CMR) flow-velocity and non-invasive central blood pressure (cBP) waveforms.

METHODS AND RESULTS

Two hundred and six healthy volunteers (age range 21-73 years, 47% male) underwent sequential phase contrast CMR (Siemens Aera 1.5 T, 1.97 × 1.77 mm2, 9.2 ms temporal resolution) and supra-systolic oscillometric cBP measurement (200 Hz). Velocity (U) and central pressure (P) waveforms were aligned using the waveform foot, and local wave speed was calculated both from the PU-loop (c) and the sum of squares method (cSS). These were compared with CMR transit time derived aortic arch pulse wave velocity (PWVtt). Associations were examined using multivariable regression. The peak intensity of the initial compression wave, backward compression wave, and forward decompression wave were 69.5 ± 28, -6.6 ± 4.2, and 6.2 ± 2.5 × 104 W/m2/cycle2, respectively; reflection index was 0.10 ± 0.06. PWVtt correlated with c or cSS (r = 0.60 and 0.68, respectively, P < 0.01 for both). Increasing age decade and female sex were independently associated with decreased forward compression wave (-8.6 and -20.7 W/m2/cycle2, respectively, P < 0.01) and greater wave reflection index (0.02 and 0.03, respectively, P < 0.001).

CONCLUSION

This novel non-invasive technique permits straightforward measurement of wave intensity at scale. Local wave speed showed good agreement with PWVtt, and correlation was stronger using the cSS than the PU-loop. Ageing and female sex were associated with poorer ventriculo-arterial coupling in healthy individuals.

Standardising clinical outcomes measures for adult clinical trials in Fabry disease: A global Delphi consensus

BACKGROUND

Recent years have witnessed a considerable increase in clinical trials of new investigational agents for Fabry disease (FD). Several trials investigating different agents are currently in progress; however, lack of standardisation results in challenges to interpretation and comparison. To facilitate the standardisation of investigational programs, we have developed a common framework for future clinical trials in FD.

METHODS AND FINDINGS

A broad consensus regarding clinical outcomes and ways to measure them was obtained via the Delphi methodology. 35 FD clinical experts from 4 continents, representing 3389 FD patients, participated in 3 rounds of Delphi procedure. The aim was to reach a consensus regarding clinical trial design, best treatment comparator, clinical outcomes, measurement of those clinical outcomes and inclusion and exclusion criteria. Consensus results of this initiative included: the selection of the adaptative clinical trial as the ideal study design and agalsidase beta as ideal comparator treatment due to its longstanding use in FD. Renal and cardiac outcomes, such as glomerular filtration rate, proteinuria and left ventricular mass index, were prioritised, whereas neurological outcomes including cerebrovascular and white matter lesions were dismissed as a primary or secondary outcome measure. Besides, there was a consensus regarding the importance of patient-related outcomes such as general quality of life, pain, and gastrointestinal symptoms. Also, unity about lysoGb3 and Gb3 tissue deposits as useful surrogate markers of the disease was obtained. The group recognised that cardiac T1 mapping still has potential but requires further development before its widespread introduction in clinical trials. Finally, patients with end-stage renal disease or renal transplant should be excluded unless a particular group for them is created inside the clinical trial.

CONCLUSION

This consensus will help to shape the future of clinical trials in FD. We note that the FDA has, coincidentally, recently published draft guidelines on clinical trials in FD and welcome this contribution.

Impact of obesity on myocardial microvasculature assessed using fully-automated inline myocardial perfusion mapping CMR

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Guy"s and St Thomas" Charity University College London Hospitals Biomedical Research Centre

Background

Obesity and cardiovascular disease are associated, but the relationship is poorly understood. Myocardial perfusion, metabolic derangement and lipotoxicity appear adversely associated in many scenarios (myocardial injury, diastolic dysfunction, diabetes). Altered perfusion (by PET) predicts outcome, and it is hypothesised that perfusion derangement is part of causality for cardiac disease and adverse outcomes.

Purpose

To assess the presence and pattern of myocardial microvascular dysfunction in patients with obesity (scheduled for bariatric surgery) using stress quantitative perfusion mapping.

Methods

38 subjects with obesity planned to undergo bariatric surgery and 38 age and sex matched healthy volunteers (no diabetes, no hypertension) underwent anthropometry, biochemistry and CMR at 1.5T (Siemens) with cine imaging, stress (adenosine 140-210 mcg/kg/min) and rest fully-automated quantitative perfusion mapping. 

Results

Bariatric patients had a higher BMI (44 ± 6.4 vs 26.5 ± 4kg/m2 p = 0.001); 58%(22) were diabetic and 58%(22) had hypertension. Bariatric patients had higher absolute but lower indexed end-diastolic volumes, and overall higher ejection fractions (+5%) (see Table). Rest myocardial blood flow (MBF) in bariatric patients was the same (1.00 ± 0.3 vs 0.88 ± 0.24 p = 0.052), but stress perfusion results were significantly lower both for stress MBF (2.35 ± 0.69 vs 2.93 ± 0.76ml/g/min p = 0.001) and myocardial perfusion reserve (MPR 2.48 ± 0.82 vs 3.4 ± 0.81ml/g/min p = 0.0001).  Although this was transmural, the endocardial stress MBF was particularly negatively affected in the bariatric cohort compared to controls (endocardial MBF 2.16 ± 0.65 vs 2.82 ± 0.73ml/g/min, p = 0.0001 vs epicardial MBF: 2.52 ± 0.76 vs 3.06 ± 0.79 p = 0.003), meaning there was an increased endo-epicardial stress MBF gradient in bariatric patients (0.87 ± 0.12 vs 0.92 ± 0.07 p = 0.03).

Conclusion

Compared to healthy controls, patients with obesity have abnormal myocardial stress perfusion with reduced global perfusion, perfusion reserve and an increased transmyocardial perfusion gradient.

Table - myocardial perfusion parameters Category Bariatric patients n = 38 Controls n = 38 p value Age (years) 48 ± 11 45 ± 13 0.25 n male (%) 12 (32%) 10 (36%) 0.32 LVEDV (ml) 168 ± 37 149 ± 31 0.017 LVEDVi (ml/m2) 70.4 ± 12.3 78.8 ± 12.1 0.004 LV Mass (g) 116 ± 31 99 ± 28 0.019 EF (%) 70 ± 8 65 ± 5 0.002 LVEDV - left ventricular end-diastolic volume, EF - ejection fraction

Influences on myocardial perfusion in non-obstructive coronary disease: an observational quantitative perfusion mapping study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): This study was supported by a Clinical Training Research Fellowship (K. Knott) from the British Heart Foundation and directly and indirectly from the Biomedical Research Centre at University College London Hospitals and Barts Heart Centre.

Background

Cardiovascular magnetic resonance (CMR) with automated inline perfusion mapping permits rapid fully automated non-invasive myocardial blood flow (MBF, ml/g/min). Understanding the microvascular component of MBF would help optimize epicardial coronary artery disease detection and potentially serve as an independent diagnostic / therapeutic target. 

Purpose

To explore MBF influences at stress and rest in patients with unobstructed epicardial coronary arteries.

Methods

242 participants (mean age 56.9 years) from 5 European centers with unobstructed epicardial coronary arteries and no myocardial scar underwent adenosine vasodilator perfusion mapping at stress and rest. The factors influencing MBF were determined using univariate and multivariate linear regression analyses.

Results

Mean rest perfusion was 0.91+/-0.24ml/g/min. Rest perfusion was higher in females (0.97+/-0.22ml/g/min vs 0.83 +/- 0.24ml/g/min) and lower in patients on beta blockers. Mean stress MBF was 2.53+/-0.82ml/g/min. Factors independently associated with reduced stress MBF were increasing age, diabetes, increasing left ventricular mass (LVMi) and the use of beta blockers.  The predicted stress MBF can be obtained from the equation MBF = 2.66–0.015(age-60)–0.013(LVMi-57)-0.405(diabetes)–0.365(beta blocker). This means stress MBF falls 10% over 19 years and that diabetes drops the MBF by the equivalent of being 27 years older. These changes are large: for example, a 70-year-old diabetic would have 30% lower stress MBF than a 35 year-old non-diabetic. 

Conclusions

In the absence of obstructive epicardial coronary disease, stress MBF falls with age, diabetes, increased LV mass and beta-blockers. These data may help develop normal reference ranges, input to other modelling (eg CT FFR), and they advance perfusion mapping as a measure of microvascular function.

Abstract Figure. Summary of the determinants of perfusion

AS-amyloidosis. Dual pathology or novel disease? A multimodality, multi-centre assessment across health and disease

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

onbehalf

AS-Amyloidosis consortium

Background

The coexistence of severe aortic stenosis (lone AS) and transthyretin cardiac amyloidosis (lone amyloidosis) is common, but the resultant AS-amyloidosis phenotype is unclear.

Purpose

We characterised AS-amyloidosis, hypothesizing that the dual insult of AS-amyloidosis results is a severe phenotype.

Methods

We compared four cohorts with deep phenotyping: 81 older age controls, 359 lone AS, 36 AS-amyloidosis (Perugini grade 2 and 3) and 107 lone amyloidosis (Perugini grade 2 and 3).

Results

AS-amyloidosis was similar to lone AS with respect to left ventricular mass and LVEF (57 (45, 64)%). It was similar to lone amyloidosis with respect to lateral S" (0.04 (0.03, 0.06) m/s), NT-proBNP (4149 (1449, 6459) ng/L) and troponin T (56 (34, 100) ng/L). Whilst, prevalence of carpal tunnel syndrome (CTS) (17%) and diastolic function (E/A ratio 1.1 (0.8, 2.8)) were intermediate.

Conclusion

AS-amyloidosis is not a double insult from AS and amyloidosis, but a mixed phenotype with features similar to lone amyloidosis (cardiac biomarkers), lone AS (remodelling and LVEF) or intermediate (diastology and CTS).

Characteristics across all 4 groups Variable Older age controls (n = 81) Lone AS (n = 359) AS-amyloidosis (n = 36) Lone amyloidosis (n = 107) P value Age (years) 82 (80, 84)*†‡ 85 (80, 88)§∞ 88 (85, 92)# 80 (75, 84) &lt;0.005 Sex (% male) 69 *‡ 49 ∞ 61 # 94 &lt;0.005 Carpal tunnel syndrome (%) 0 2 § 17 # 38 &lt;0.005 Voltage/mass ratio 0.22 (0.14, 0.27)‡ 0.18 (0.13, 0.28)∞ 0.18 (0.09, 0.21)# 0.07 (0.05, 0.10) &lt;0.005 NT-ProBNP (ng/L) 131 (66, 221)*†‡ 1629 (639, 3941)§∞ 4149 (1449, 6459) 2888 (1755, 5483) &lt;0.005 hsTnT (ng/L) 12 (8, 17)*†‡ 24 (15, 40)§∞ 56 (34, 100) 62 (41, 82) &lt;0.005 Inferolateral wall thickness (cm) 0.9 (0.8, 1.0)*†‡ 1.1 (0.9, 1.3)∞ 1.3 (1.1, 1.5)# 1.7 (1.6, 1.9) &lt;0.005 Anteroseptal wall thickness (cm) 1.0 (0.9, 1.2)*†‡ 1.4 (1.2, 1.6)§∞ 1.5 (1.3, 1.8) 1.7 (1.6, 1.9) &lt;0.005 Indexed LV mass (g/m2) 79 (66, 102)*†‡ 128 (99, 152)∞ 126 (116, 140)# 174 (159, 200) &lt;0.005 LVEF (%) 59 (54, 63)‡ 59 (50, 65)∞ 57 (45, 64)# 39 (31, 48) &lt;0.005 Lateral S" (m/s) 0.08 (0.07, 0.09)*†‡ 0.07 (0.05, 0.08)§∞ 0.05 (0.04, 0.07) 0.05 (0.04, 0.06) &lt;0.005 Septal S" (m/s) 0.06 (0.06, 0.08)*†‡ 0.05 (0.04, 0.06)∞ 0.04 (0.03, 0.06) 0.04 (0.03, 0.05) &lt;0.005 E/A 0.7 (0.6, 0.8)*†‡ 0.8 (0.7, 1.3)§∞ 1.1 (0.8, 2.8)# 2.4 (1.8, 3.3) &lt;0.005 RV Wall thickness (cm) 0.4 (0.3, 0.4)*†‡ 0.4 (0.4, 0.6)∞ 0.6 (0.4, 0.7)# 0.8 (0.7, 1.0) &lt;0.005 TAPSE (cm) 2.4 (2.0, 2.7)*†‡ 2.1 (1.6, 2.5)∞ 1.9 (1.5, 2.1)# 1.4 (1.2, 1.9) &lt;0.005 Classical LFLG AS (%) 9 13 0.472 * p &lt; 0.05, Old age control vs Lone AS † p &lt; 0.05, Old age control vs AS-amyloidosis ‡ p &lt; 0.05, Old age control vs Lone amyloidosis § p &lt; 0.05, Lone AS vs AS-amyloidosis ∞ p &lt; 0.05, Lone AS vs Lone amyloidosis # p &lt; 0.05, AS-amyloidosis vs Lone amyloidosis Abstract Figure. AS-amyloidosis compared to other cohorts

Pulsatile and resistive systolic loads as determinants of left ventricular remodelling after physical training

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation Barts Cardiovascular Biomedical Research Centre

onbehalf

The Marathon Study Consortium

Introduction

Cardiovascular function depends on the inter-relation between heart and vasculature.  The contribution of aorta and peripheral vessels to the total systolic load of the left ventricle (LV) can be represented respectively by a "pulsatile" and a "resistive" component. We sought to understand their interrelation by exploring how LV remodelling occurred with altered load associated with an external stimulus (training). Methods: 237 untrained healthy male and female subjects volunteering for their first-time marathon were recruited. At baseline and after 6 months of unsupervised training, race completers underwent 1.5T cardiac magnetic resonance, brachial and non-invasive central blood pressure assessment. For analysis, runners were divided into 4 groups according to the variation (positive versus null or negative) in Total Arterial Compliance Index (TACi), representing the pulsatile component of the LV load, and in Systemic Vascular Resistance Index (SVRI), representing the resistive component of the LV load. Results: 138runners (age 21-69 years; F: 51%) completed the race. Data are reported for each variable as Δ mean [95% Confidence Interval]. In the whole cohort, training was associated with a small increase in LV mass index (+3g/m2, [0, 6 g/m2]), indexed LV end-diastolic volume (EDVi) (+3ml/m2, [-2, 5 3ml/m2]), in LV mass/LVEDV ratio (+0.02g/ml, [0.00, 0.04 g/ml]) and in TACi (+0.02ml/m2, [0.02, 0.38 ml/m2]). SVRi mildly fell (-43dyn·s/cm2[-103, 17dyn·s/cm2]). TACi increase was associated with LVEDVi increase and no change in LV mass/EDV (eccentric remodelling). On the other hand, both TACi reduction and SVRi increase were associated with increase in LV mass/EDV and no significant change in LVEDVi (concentric remodelling). A similar increase in LV mass was observed in all groups. See Table. Conclusion: Cardiac remodelling observed after mild, medium term, unsupervised training seems to be related to the modifications of aorta and peripheral vessels. In particular, a reduction in pulsatile load seems associated with eccentric LV remodelling, while an increase in both pulsatile and resistive with concentric LV remodelling. Further research is needed to understand the interaction between TACi and SVRi.

Table 1 LV EDVi (ml/m2) LV mass index (g/m2) LV mass/EDV TACi increase (n = 75) +4 [0, 9] +3 [0, 7] 0 [-0.03, 0.03] TACi decrease (n = 62) -1 [-6, 4] +3 [0, 8] 0.04 [0.01, 0.07] SVRi increase (n = 63) 0 [-4,4] +3 [0, 7] +0.03 [0, 0.06] SVRi decrease (n = 73) +3 [-3, 7] +3 [-1, 6] +0.01 [-0.02, 0.04]

Myocardial fibrosis quantification by cardiac CT predicts outcome in severe aortic stenosis

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Background

Myocardial extracellular volume (ECV) increases with fibrosis, oedema or infiltration. ECV by CMR predicts all-cause and cardiovascular mortality in severe AS after valve intervention. Previous studies have shown that ECV can be reliably quantified by computed tomography (ECVCT), but these studies have not differentiated between ECV elevation due to fibrosis or cardiac amyloid deposition (13-16% of patients with severe AS). 

Purpose

We hypothesised that ECVCT quantification, performed as part of a transcatheter aortic valve implantation (TAVI) work-up CT, predicts survival in patients with severe AS without cardiac amyloid (lone AS).

Methods

Patients aged ≥75, with severe AS, referred for TAVI at Barts Heart Centre (as part of ATTRact-AS (NCT03029026)) underwent CT as part of their clinical work-up. All patients had 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy and those with a positive result were excluded.  CT was performed on a 128-slice dual-source 3rdgeneration scanner (Siemens Somatom FORCE) and ECVCT was acquired during the TAVI work-up CT using additional pre- and 3-minute post-contrast ‘axial shuttle mode’ acquisitions (no additional contrast).  ECVCT was calculated from the Hounsfield units (HU) and a venous haematocrit (HCT): ECVCT = (1-HCT) x (ΔHUmyo/ΔHUblood).

Results

Following exclusion of 16 patients with cardiac uptake on DPD, 93 patients (41% male, aged 85 ± 5 years) were included in the study.  All patients had severe AS (AV Vmax 4.12 ± 0.63m/s, mean AV gradient 42 ± 14mmHg, AVA 0.71 ± 0.23cm2). The mean HCT was 0.38 ± 0.04 and total dose-length product for additional research scans was 364 ± 41 mGy.cm. 76 patients (82%) underwent TAVI. ECVCT was 32 ± 3% in the entire cohort, which we then split into those with a ‘higher’ ECVCT (&gt;34%, n = 23, representing the highest quartile) and those with a ‘lower’ ECVCT (≤34%, n = 70, representing the lower quartiles). Over a median follow-up of 25 months (IQR 17-34 months) there were 27 deaths (29%), of whom 11 did not undergo TAVI (41%). There were 10 deaths in the 23 patients (44%) with a higher ECVCT, compared to 17 in the 70 patients (24%) with a lower ECVCT (p = 0.03, figure 1). This mortality difference remained significant when those patients who did not undergo TAVI were excluded (p = 0.03).

Conclusions

Myocardial fibrosis quantified by ECVCT is associated with a significantly worse prognosis in lone AS, even after patients with AS-amyloid are excluded. ECVCT can be performed as a simple addition to the TAVI work-up CT and provides additional prognostic information.

Abstract Figure.

Left ventricular remodelling in masters athletes

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): I have received a research fellowship grant from the UK based charity Cardiac Risk in the Young

Objectives

We investigated the effect of long-term exercise and sex on left ventricular (LV) geometry in a large group of female and male masters athletes.

Background

Studies assessing LV geometry in masters athletes are scarce.

Methods

Different types of LV geometry were identified according to echocardiography-derived relative wall thickness (RWT) and left ventricular mass (LVM) values as per international guidelines. 4 groups were formed: normal (normal LVM/normal RWT), concentric hypertrophy (increased LVM/increased RWT), eccentric hypertrophy (increased LVM/normal RWT), and concentric remodeling (normal LVM/increased RWT).

Results

A total of 277 healthy, elite, caucasian endurance masters athletes (65% female; mean age54.8 ± 7.7 years) were assessed. The athletes were exercising for a mean 32 ± 11.7 years and have completed a median 70 competitions including a median 13 marathon-type competitions. Females exhibited lower absolute LVM (127.7 ± 30.31g vs 196.57 ± 45.0g, p &lt; 0.001), indexed LVM (76.8 ± 18.0 g/m2 vs. 103.6 ± 22.7 g/m2; p &lt; 0.001), RWT (0.36 ± 0.07 vs. 0.42 ± 0.08; p &lt; 0.001) and absolute LV end-diastolic dimension (LVEDD) (46.3 ± 4.1 mm vs 50.1 ± 5.11 mm, p &lt; 0.001) but greater indexed LVEDD (27.7 ± 2.7mm/m2 vs 26.5 ± 2.7 mm/m2, p &lt; 0.001) compared with male athletes. Most female athletes showed normal LV geometry (72% vs 38% in male athletes, P &lt; 0.001) and significantly less concentric remodeling (12% vs 35%, p &lt; 0.001) and concentric hypertrophy (5% vs 13%, p = 0.01) (table & figure).

Conclusions

A sex-specific response to chronic exercise is observed. Male masters athletes exhibit significantly more frequently abnormal LV geometry with concentric LV remodeling and/or concentric hypertrophy.

Cohort characteristics Male masters athletes N = 97 Female masters athletes N = 180 P value Age (years) 55.0 ± 9.0 54.7 ± 6.9 0.68 Years of exercise 32.0 ± 12.8 33.3 ± 11.1 0.14 LV Mass (g) 127.7 ± 30.31 196.57 ± 45.0 &lt;0.001 LV Mass Indexed (g/m2) 76.8 ± 18.0 103.6 ± 22.7 &lt;0.001 LVEDD (mm) 46.3 ± 4.1 50.1 ± 5.11 &lt;0.001 LVEDD Indexed (mm/m2) 27.7 ± 2.7 26.5 ± 2.7 &lt;0.001 Normal Remodeling 36 (37) 130 (72) &lt;0.001 Eccentric Hypertrophy 14 (14) 18 (10) 0.27 Concentric Remodeling 34 (35) 23 (13) &lt;0.001 Concentric Hypertrophy 13 (13) 9 (5) 0.01 LV Left Ventricular, LVEDD: Left Ventricular End Diastolic Dimension Abstract Figure. Patterns of left ventricular remodeling

623 Short-term reversed remodeling post aortic valve intervention

Background

LV remodeling in AS can cause LV hypertrophy, interstitial fibrosis and reduced contractility. SAVR or TAVI are the mainstay treatment for symptomatic severe AS. Speckle tracking has the potential to detect early signs of reverse cardiac remodeling but such LV deformation data post-SAVR/TAVI is currently lacking.

Aim

To assess the early impact of LV unloading post-TAVR/SAVR using STE.

Methods

This prospective single-center study recruited 122 patients with varying degrees of AS who underwent resting transthoracic echocardiography with offline speckle-tracking. During the follow-up period, 50 patients underwent TAVI and 15 had SAVR.

Results

Patients were followed-up for a period of 4 ± 2 weeks post-intervention. Table 1 summaries the echocardiographic findings of patients pre- and post-intervention. AV peak velocity and mean pressure gradient dropped significantly immediately after intervention in both groups. AV intervention resulted in early improvements in all myocardial deformation parameters (Figure 1). There was a significant improvement in GLS and GRS irrespective of the intervention type. While SAVR led to a significant early improvement in GCS.

Conclusion

AV Intervention in severe symptomatic AS translates into an immediate and measurable improvement in LV deformation parameters. To our knowledge this is the first echocardiographic evidence of reverse remodeling early after SAVR and TAVI.

Table 1 TAVI (n = 50) SAVR (n = 15) Variables Pre Post P* value Pre Post P* value P value┼ AV vel.(m/s) 4.4 ± 0.8 2.2 ± 0.5 &lt;0.001 4.5 ± 0.8 2.2 ± 0.5 &lt;0.001 NS AV mPG (mmHg) 44.3 ± 16.2 9.7 ± 3.9 &lt;0.001 44.6 ± 19.2 9.8 ± 4.8 &lt;0.001 NS GLS (%) -10.9 ± 3.6 -13.9 ± 3.1 &lt;0.001 -13.7 ± 4.5 -17.7 ± 3.9 0.002 NS GCS (%) -29.2 ± 9.1 -32 ± 9.5 NS -28.6 ± 9.8 -34.9 ± 5.1 0.032 NS GRS (%) 42.0 ± 15.1 47.2 ± 13 0.024 34.7 ± 12.5 41.4 ± 9.9 0.04 NS EDV (ml) 87.29 ± 55.3 89.8 ± 38.6 NS 104.3 ± 25.1 83.2 ± 41.9 NS NS ESV (ml) 45.1 ± 39.4 36.6 ± 29.1 NS 42.8 ± 17.7 28.6 ± 18.6 0.03 NS SV (ml) 59.7 ± 23.6 55 ± 19.3 NS 65.5 ± 17.9 57.2 ± 22.7 NS NS SVi (ml/m2) 33.1 ± 12.7 30.4 ± 9.6 NS 34.1 ± 8.3 29.8 ± 11.1 NS NS LV mass (g) 185.7 ± 53.6 183.3 ± 48. NS 177.5 ± 48.4 169.5 ± 52.2 NS NS LVMi (g/m2) 103.6 ± 30 102.1 ± 25.9 NS 93.8 ± 29.9 89.4 ± 24.2 NS NS Biplane EF (%) 58 ± 15 62 ± 13 0.013 60 ± 9 66 ± 6 &lt;0.05 NS AV: Aortic valve; EDV: end diastolic volume; EF: ejection fraction; ESV: end systolic volume; GCS: Global circumferential strain; GLS: Global longitudinal strain; GRS: Global radial strain; LV: left ventricle; LVMi: left ventricular mass index; mPG: mean pressure gradient; SV: stroke volume; SVi: stroke volume index; Vel: velocity Data are expressed as mean ± SD. Comparisons were performed using paired Student"s t tests(parametric) or Wilcoxon paired test (non-parametric). *Pre and post intervention. ┼Comparison of pre/post-intervention measurement difference between the two intervention groups done using unpaired t-test

Abstract 623 Figure.

618 Adaptive myocardial mechanics in aortic stenosis patients

Introduction

Left ventricular (LV) hypertrophy in aortic stenosis (AS) becomes maladaptive over time, leading first to a reduction in global longitudinal strain (GLS) and in a later stage a reduction in ejection fraction (EF). The myocardial state of impaired GLS but preserved EF is a key remodeling turning point in AS, yet little is known about the coping mechanics of the LV at or around this sensitive juncture.

Aim

1) To study the relationship between LV mass index (LVMi) increase and measures of LV function, including strain in AS; 2) To investigate whether augmentation of global myocardial radial and circumferential strain (GRS, GCS) compensates for the GLS reduction in AS patients with preserved EF.

Methods

One-hundred and eleven patients with varying degrees of AS, and 20 age- and gender-matched healthy volunteers were prospectively enrolled. transthoracic echocardiography with offline strain analysis was performed using TomTec software. Intra- and inter-observer variability of linear LV internal dimensions/thickness, EF and strain indices was tested on 20 randomly selected patients.

Results

Clinical and demographic characteristics of cases and controls are shown in Figure 1. GLS was impaired in AS patients compared to controls. In AS with preserved EF (&gt;50%), as LVMi increased, GLS progressively improved up to a point, beyond which any further increase in LVMi appeared counter-productive with impairment of GLS (Figure 1). EF preservation in these AS patients was mediated by a compensatory supernormal augmentation of GRS and a smaller augmentation of GCS (Figure 1). We observed a significant inverse correlation between GRS and GLS (r = 0.3, p = 0.002), and a similar trend between GCS and GLS (r = 0.275, p = 0.004). Intraclass correlation coefficient was high for all measurements (0.7-0.9).

Conclusion

In patients with AS and preserved EF, progressive myocardial hypertrophy improves GLS up to a point beyond which GLS drops and GRS increase to compensate. This plasticity of myocardial mechanics, in particular the supranormal augmentation of GRS is what enables the pathologically hypertrophied AS ventricle to delay the otherwise inexorable decline in its global systolic function.

Abstract 618 Figure 1

Making MRI available for patients with cardiac implantable electronic devices: growing need and barriers to change

Abstract

More than half of us will need a magnetic resonance imaging (MRI) scan in our lifetimes. MRI is an unmatched diagnostic test for an expanding range of indications including neurological and musculoskeletal disorders, cancer diagnosis, and treatment planning. Unfortunately, patients with cardiac pacemakers or defibrillators have historically been prevented from having MRI because of safety concerns. This results in delayed diagnoses, more invasive investigations, and increased cost. Major developments have addressed this—newer devices are designed to be safe in MRI machines under specific conditions, and older legacy devices can be scanned provided strict protocols are followed. This service however remains difficult to deliver sustainably worldwide: MRI provision remains grossly inadequate because patients are less likely to be referred, and face difficulties accessing services even when referred. Barriers still exist but are no longer technical. These include logistical hurdles (poor cardiology and radiology interaction at physician and technician levels), financial incentives (re-imbursement is either absent or fails to acknowledge the complexity), and education (physicians self-censor MRI requests). This article therefore highlights the recent changes in the clinical, logistical, and regulatory landscape. The aim of the article is to enable and encourage healthcare providers and local champions to build MRI services urgently for cardiac device patients, so that they may benefit from the same access to MRI as everyone else.

Key Points

• There is now considerable evidence that MRI can be provided safely to patients with cardiac implantable electronic devices (CIEDs). However, the volume of MRI scans delivered to patients with CIEDs is fifty times lower than that of the estimated need, and patients are approximately fifty times less likely to be referred.

• Because scans for this patient group are frequently for cancer diagnosis and treatment planning, MRI services need to develop rapidly, but the barriers are no longer technical.

• New services face logistical, educational, and financial hurdles which can be addressed effectively to establish a sustainable service at scale.

2395LGE CMR predicts sudden death and VT in adults with repaired tetralogy of Fallot - a prospective study with 3500 patient follow up years

Background

Adults with repaired tetralogy of Fallot (rtoF) are at risk of ventricular arrhythmia and sudden cardiac death (SCD). Cross-sectional data suggest association of late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) with adverse clinical risk factors

Purpose

We sought to determine prognosis related to LGE CMR.

Methods

In this prospective cohort study the primary composite outcome comprised the first of cardiovascular death (SCD or heart failure-related), aborted SCD (successfully resuscitated cardiac arrest or appropriate AICD shock for ventricular fibrillation), and clinical sustained ventricular tachycardia (VT>30 seconds duration).

Results

In 531 rtoF patients (median age 32; 23–42, 296 (56%) male, NYHA≥II 17%) followed up after LGE CMR for median 5 (1.7–8.9) years, there were 39 primary composite outcomes: 10 SCD, 11 heart failure related deaths (2 perioperative RV failure), 2 aborted SCD and 16 clinical sustained VT events. At study end, there were 28 ventricular arrhythmic events in 28 rtoF patients (10 SCD, 16 clinical sustained VT, 2 aborted VF) that were significantly predicted by RV LGE extent (HR 1.45 CI: 1.3–1.6; P<0.001).

Univariable predictors of the primary outcome were RV LGE score; HR: 1.44 (1.31–1.57; p<0.001), (Figure) together with older age; HR: 1.05 (1.02–1.07; P<0.001), late repair; HR: 1.04 (1.02–1.07; p<0.001), lower RV ejection fraction; HR: 0.92 (0.89–0.95; p<0.001), larger RVOT akinetic length; HR: 1.04 (1.02–1.06; p<0.001) larger right atrial area; HR: 1.2 (1.12–1.29; p<0.001); higher BNP levels; HR: 1.01 (1–1.02; p<0.001), lower peak VO2; HR: 0.89 (0.83–0.96; p=0.001), prior atrial arrhythmia; HR: 5.3 (2.8–10.07; p<0.001), and non-sustained VT; HR: 4.1 (2.1–7.7; p<0.001). Inducible VT did not predict the primary outcome; HR: 2.1 (0.57–8; p=0.25)

In multivariable analysis both RV LGE score and indexed right atrial area (RAAi) only, remained predictive of the primary outcome (HR 1.29 CI: 1.12–1.49; p<0.001 and HR 1.1 CI: 1.02–1.12; p=0.01, respectively). Patients could accordingly be stratified such that supramedian RV LGE score (≥5) and RAAi ≥16cm2/m2 had 5-year event free survival 84% vs 94% for supramedian RV LGE score (≥5) and RAAi <16cm2/m2 or 98% for inframedian RV LGE score with RAAI<16cm2/m2. Figure.

Conclusions

For every unit increase in CMR defined RV fibrosis score there is a 44% increased risk of sudden cardiac death and VT. LGE CMR and maximal right atrial area should therefore be incorporated into risk stratification for sudden death in adults with rTOF.

Acknowledgement/Funding

British heart foundation

P340Inflammatory cardiomyopathy in Fabry disease

Background

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in α-galactosidase A. Cardiovascular magnetic resonance (CMR) has helped unveil the pathogenesis of Fabry cardiomyopathy: sphingolipid storage (low T1 mapping values), left ventricular hypertrophy (LVH) and myocardial fibrosis with late gadolinium enhancement (LGE) characteristically present in the basal inferolateral (BIFL) wall. Recent evidence has suggested that the LGE may be inflammation and oedema as part of this pathogenic process.

Purpose

To assess the presence of inflammation in patients with FD using T2 mapping (for oedema/inflammation) supported by blood troponin levels (showing myocyte death and by inference inflammation).

Methods

A multi-centre international study in gene positive FD patients using CMR and blood biomarkers. All participants underwent CMR at 1.5 T. Native T1 and T2 mapping were performed. The T1 mapping sequence was MOLLI with sampling scheme in seconds. LGE used a phase sensitive inversion recovery sequence. Global longitudinal 2D strain (GLS) values were obtained using feature tracking analysis. Blood high-sensitivity troponin T (hsTnT) was measured on the same day.

Results

100 FD patients (age 43.8±1.3 years, 42% male) were included. 45% had LVH, 35% LGE. Low T1 mapping (normal <943ms) was found in 49% and 33% had high hsTnT values (normal <15ng/L). Mean T2 mapping values were 52.6±0.6ms in the BIFL wall and 49.5±0.3ms in the remote myocardium/septum (p<0.001, normal <53ms). T2 values in the BIFL wall were significantly higher among patients with LGE (58.2±6.1ms vs 49.2±3.1ms, p<0.001, Figure 1). In a per-segment analysis of 1600 segments, higher T2 values correlated positively with percentage of LGE per segment (r=0,262, p<0.001), T1 values (r=0,205, p<0.001), maximum wall thickness (r=0,253, p<0.001) and GLS values (r=0,212, p<0.001). HsTnT values were higher among patients with LGE (median of 31 vs 3ng/L in patients without LGE, p<0.001). There was a strong positive correlation between T2 values in the BIFL wall and ln(hsTnT) (r=0.776, p<0.001, Figure 2). The strongest predictor of increased hsTnT in multivariate analysis (age, sex, LVH, septum T1, T2 in the BIFL, GLS, LGE) was T2 in the BIFL wall (β=0.4, p=0.001).

Conclusions

Cardiac involvement in FD goes beyond storage (low T1 values). When LGE is present, this is almost always associated with a high T2 and troponin elevation supporting FD as a chronic inflammatory cardiomyopathy. Initial reports of LGE being fibrosis are too simplistic – LGE in FD appears to have a significant chronic inflammation/oedema component.